function findByName() {
	$.ajax({ 
        url: "queryUsername.do", 
        data: "username=" + $("#username").val(),  
        type: "GET",  
        dataType: 'json',   
        contentType: "application/json; charset=utf-8",
        error:function(data){  
            alert("发生错误");  
        },  
        success:function(data){
            if(data == 'findusername'){
            	alert("用户名已存在");
            	document.getElementById("name").value="";
            }  
        }
   });  
}
